CLOUDSTACK-4300: possible fix: cputune feature is only available after 0.9.0, so start vm can fail on rhel 6.1
CLOUDSTACK-4325: add more test cases for zone wide storage pool allocator
CLOUDSTACK-3229: if delete snapshots on staging area failed, still treat backup snapshot as succeed. And modify snapshot delete logic on devcloud
CLOUDSTACK-4363: fix possible NPE, if copy volume failed.
CLOUDSTACK-4338: fix NPE if create volume failed
fix unit test
CLOUDSTACK-4324: delete snapshot_store_ref, if create snapshot failed on primary storage
Merge remote-tracking branch 'github/master' into vxlan-master
Dedupe execute(CheckOnHostCommand)
Merge remote-tracking branch 'github/vxlan-master' into vxlan-master